I am beginning stages of planning for a re-gear and am looking for some expert advice in the planning. I installed a 4" lift and put on 315/70R17's (34's) . As I suspected, the performance has suffered. My rig is a Sahara with an automatic transmission, a Dana 44 in back with ltd slip differential, and a Dana 30 in front. The towing package means I have 3.73 gears from the factory. My factory tires were 255/70R18's (32's), so as a minimum I would have to go up to 4.10's to achieve any improvement at all.

I have attached images of the speedo and tach taken with the factory tires at speeds of 60 & 70 mph. As you can see the tach shows 1700 & 2000 rpm, respectively. It's funny the rpm's seem to indicate a number more indicative of me having 4.10 gears, but my paper work shows 3.73. I may have to do the old spin the rear tires and count the rotation of the drive shaft trick to confirm the gears. Anyway, here are the pics.

60 mph/1700 rpm

70 mph/2000 rpm

With all that said, here are my questions.

From everything I've seen, 5.13's seem like the best (max possible in Dana 30), and I know they will give me the most punch, but will it be at the cost of fuel economy? This is my DD, so fuel economy is important. There are also 4.10, 4.56, & 4.88 gears available and I want the best compromise between punch and economy. This is where the experts with real-time experience will help me the most.

How much should I expect to budget on having them installed professionally and who can recommend someone good? I do not have the tools needed to accomplish the re-gear myself, and quite frankly, having heard some of the nightmares about failed installations, makes me leery of even attempting it.

What brand is the best, or does it even matter? Has anybody had any awful experiences with any of them?

I've read Constantine's thread "Gears" and it was actually very helpful. I don't mind spending the money, I am just afraid of wasting it, which is why I'm very cautious and analyze the he77 out of everything before pulling the trigger. Thanks in advance for your opinions and help!

Wow, that was way longer then I thought it would be. I tend to do that though.

Question - do you plan to upgrade the front axle? If so, buy that first so you're only doing one complete regear.

I would suspect that your fuel economy between 5:13's and 4:88's would be a minimal impact.

As far as installs, Rock Rash can do it and there's even a place that advertises on the Houston Craiglist forum. I've seen gear install specials that are around $800-900. I don't believe that they replace any bearings for that price.

Thanks for the feedback fella's. I'm getting ready to leave the office and decided to check in on my thread.

Before my lift and tires went on I could count on a tank of gas averaging me between 16 & 18 mpg. Now I'm showing 13 & 14. I know my speedo is whacked right now so I am not too concerned. But, at the same time, I know everything is suffering. I can feel the performance difference with the larger tires and I know a Superchip might adjust some of that out. I know that a re-gear is realistically the only way to see improved response out of the vehicle.

I would imagine that the Superchip would be good for dialing in performance, but not wholesale improvements. I guess my biggest fear is dropping $2k to re-gear and then realizing that my fuel economy still sucks. I would like to be able to get back around the stock economy if possible.

Thanks again for your feedback. I'm sure I am going to get a lot more advice/feedback from others. I'm counting on it, actually.

Herjk is running 5:13 with 35's and love them and I think paulie did the swap himself

Yep, I've heard that Paulie is a gearing guru. I almost PM's Herjk rather than post up a new thread. The reason I didn't was because I thought I might get a broader range of expert opinions based upon personal experiences with different gear ratios. I am hoping that Paulie responds too though (hint, hint).

Hemi_Tim aka thebigtman wrote:

Hook-Em,

You won't be back to the stock fuel economy ever again no matter what you do (unless that means going back to stock).

But seriously, I figured I would never get back to that mark without going back to stock, and that just ain't hapnin. I would like to get closer rather than further and eliminate the gutlessness I have now though. I know the Superchip may help with the efficiency a bit, but I figure the re-gear would be needed to cure the gutlessness. I'm not a heavy-footed driver anyway, but there are times when I like/need a little more response than a cruise ship. Just sayin'.

I'm gonna send that to Master-Card. Maybe the royalties will fund the mods.

matinau wrote:

remember, if your speedo is wacked, so will your mpg calculations.

I show 8 on calculations for my DD, but doubt it's that low. you get used to it after awhile. just stop checking it and you'll be fine.

Yep, I know my mpg's are whacked too. I think I can manually account for the delta due to the change in tire sizes and then manually calculate the actual mpg. However, I know the news is not going to be good and it seems too counter-productive to spend the time figure out the magnitude of the bad news.

Oh, wait. Maybe I could get really geeky (I am an engineer) and figure out the cost per day for the change and then use it to justify the $1500 to $2000 expense of re-gearing. Anything to justify another mod right?

I don't think I could ever not keep track of my mileage. I've been doing it for too long now.

fwiw, with 32's, 3.23 gears, and a six speed, I haven't hit 15 mpg in about 2 years now. Average 12 to 14. It has always been my opinion that 3.23 is not enough gear to turn a 32" tire on this heavy vehicle and that it can actually hurt gas mileage. There are times out on the highway that it feels like Maverick's old 4 cylinder yj on 33's.

Also retiring/gearing in the next month or two and over compensating for the 33's by going to 4.88's. Do they make a detroit locker for our jk d44's yet? sorry for the slightly off topic question.

Hey guys, sorry for the late response, we just got back from Vegas and the Sema show.

Hook-Em, first Paulie wants to know if you plan on going bigger than 35's on your jeep? He agrees with Tim and would hate for you to spend the money on the dana 30 when you can spend it on upgrading to a dana 44.

Honestly, it would be a lot easier to just call Paulie @ 210-385-5060. If he doesn't answer just leave him a voicemail.

Just ordered a Detroit Locker Trutrac, 4.10 gears front and back, master rebuild kit for D44 and install kit for D30. $1180.00 with lifetime warranty. Still have to get outer seals, bearings, and brakes.

Hey guys, sorry for the late response, we just got back from Vegas and the Sema show.

Hook-Em, first Paulie wants to know if you plan on going bigger than 35's on your jeep? He agrees with Tim and would hate for you to spend the money on the dana 30 when you can spend it on upgrading to a dana 44.

Honestly, it would be a lot easier to just call Paulie @ 210-385-5060. If he doesn't answer just leave him a voicemail.

I just dropped $3300 on a lift, tires and wheels. I don't think a Dana 44 is in the cards right now. That would likely be another $3500 or more (unless somebody is giving them away ). I'll call Paulie tomorrow sometime. Thanks!

mb817 wrote:

i just had 513s front locker and trans cooler install parts and labor for 1,600.oo what a diff from those 373s.

The whole job: gears, locker, and cooler with parts and labor $1600? That's outstanding!!! I wouldn't think you could get the parts alone for that price.

Hemi_Tim aka thebigtman wrote:

If are going to do a regear maybe we can get a couple rigs together and give Paulie or whomever some additional business. I need to do mine.

I can have Marcus at River City Offroad give us a package price once we know exactly what we want.

I'm open for anything that will make the cost go down and still get the job done.

Just curious cuz I'm about to lock front and rear with a detroit in the rear. Why would I not want to do this to my daily driver? Is it just the annoyance factor? Keep in mind my daily driver hasn't had a sway bar on it in over 2 years and 40k miles...